Nanocrystalline cellulose as an additive in golf balls

ABSTRACT

The present invention is directed to a golf ball and, more particularly, a golf ball having a polybutadiene based core, a cover disposed about the core, and optionally an intermediate layer disposed between the core and the cover. In one embodiment, at least one or more portions of the core, cover, or intermediate layer comprises a blend of thermoplastic or thermoset material and about 1 to 10 pphr of a nanocrystalline cellulose material.

FIELD OF THE INVENTION

The present invention is directed to a golf ball and, more particularly, a golf ball having a polybutadiene based core, a cover disposed about the core, and optionally an intermediate layer disposed between the core and the cover. In one embodiment, at least one or more portions of the core, cover, or intermediate layer comprises a blend of thermoplastic or thermoset material and about 1 to 10 pphr of a nanocrystalline cellulose material.

BACKGROUND OF THE INVENTION

Conventional golf balls can be divided into several general classes: (a) solid golf balls having one or more layers, and (b) wound golf balls. Solid golf balls include one-piece balls, which are easy to construct and relatively inexpensive, but have poor playing characteristics and are thus generally limited for use as range balls. Two-piece balls are constructed with a generally solid core and a cover and are generally the most popular with recreational golfers because they are durable and provide maximum distance.

Balls having a two-piece construction are commonly formed of a polymeric core encased by a cover. Typically, the core is formed from polybutadiene that is chemically crosslinked with zinc diacrylate and/or other similar crosslinking agents. These balls are generally easy to manufacture, but are regarded as having limited playing characteristics. Solid golf balls also include multi-layer golf balls that are comprised of a solid core of one or more layers and/or a cover of one or more layers. These balls are regarded as having an extended range of playing characteristics.

Wound golf balls are generally preferred by many players due to their high spin and soft “feel” characteristics. Wound golf balls typically include a solid, hollow, or fluid-filled center, surrounded by a tensioned elastomeric material and a cover. Wound balls generally are more difficult and expensive to manufacture than solid two-piece balls.

A variety of golf balls designed to provide a wide range of playing characteristics, i.e., the compression, velocity, “feel,” and spin, that can be optimized for various playing ability, are known in the prior art.

However, there remains a need for improved golf balls having more stiffness, durability, and reduced driver spin-rate.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a golf ball and, more particularly, a golf ball having a polybutadiene based core, a cover disposed about the core, and optionally an intermediate layer disposed between the core and the cover. In one embodiment, at least one or more of portions of the core, cover, or intermediate layer comprises a blend of thermoplastic or thermoset material and about 1 to 10 of a nanocrystalline cellulose material.

In one embodiment, the cover comprises the nanocrystalline cellulose material and is an outer core layer, an inner cover layer, or an outer cover layer. In addition, the golf ball may further comprise a coating comprising the nanocrystalline cellulose material.

The nanocrystalline cellulose material has many characteristics which are listed by way of example and without limitation. The length of the nanocrystalline material may be from about 100 to 120 nm or, more preferably, about 110 nm. The diameter of the nanocrystalline cellulose material may have a diameter about 5 to 15 nm, or, more preferably about 10 nm. The tensile strength of the nanocrystalline cellulose material is about 7,000 to 14,000 MPa, or, more preferably, about 10,000 MPa. The elastic modulus of the nanocrystalline cellulose material may be about 125 to 175 GPa, or, more preferably about 150 GPa.

In another embodiment, the core may comprise a rubber based compound comprising cis-1,4 polybutadiene rubber, a crosslinking agent comprising a metallic salt of unsaturated carboxylic acid in an amount between 10 to 50 parts per hundred of rubber, and a peroxide initiator.

In addition, the nanocrystalline cellulose material may be incorporated into a golf ball during manufacturing or may incorporated into other golf equipment during manufacturing.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features which are characteristic of the present invention are set forth in the appended claims. However, the invention's preferred embodiments, together with further objects and attendant advantages, will be best understood by reference to the following detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a two-piece golf ball having a cover and a core;

FIG. 2 is a cross-sectional view of a golf ball having an intermediate layer between a cover and a core; and

FIG. 3 is a cross-sectional view of a golf ball having an intermediate layer between a cover and a core, and the cover having an inner cover layer according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed to a golf ball and, more particularly, a golf ball having a polybutadiene based core, a cover disposed about the core, and optionally an intermediate layer disposed between the core and the cover. In one embodiment, at least one or more of portions of the core, cover, or intermediate layer comprises a blend of a polymer and about 1 to 10 pphr of a nanocrystalline cellulose material to provide stiffness, durability, and reduced driver spin-rate.

Nanoparticulates are generally divided into three categories: organic, inorganic, and metallic, all of which are suitable for use in compositions for golf ball components. Because of their minute size (particle size of less than about 1000 nm), a higher concentration of particles (greater surface area) are available to interact with the surrounding polymer or rubber materials, increasing their effect on the composition many times at concentrations much lower than conventionally required.

For example, a nanomaterial, such as nanocrystalline cellulose (NCC) is extracted from wood, bacteria, cotton, tunicates, or any other cellulose source material. Nanocrystalline cellulose is a uniform, redispersible natural nanoparticle obtained from the crystalline regions of cellulose fibres. Based upon information and belief, nanocrystalline has been blended into polymers or plastics to yield up to 3000× increase in material strength. NCC is also useful in the creation of flexible films and indescent pigments used in coatings, packaging, etc. Based upon information and belief, incorporation of the nanocrystalline cellulose material into a golf ball may allow increases in the durability, shear resistance, modulus, cosmetics of the golf ball. Exemplary nanocrystalline cellulose is available from CELLUFORCE™ of Montreal, Quebec, Canada.

Because of the nanometer-sized particles have such a large surface area, small quantities of nanomaterials can have an intimate interactions and compatibility with the host matrix not available to conventional-sized particles.

Based upon information and belief, NCC may be used as a cation to neutralize or react with the ionomers while simultaneously improving their strength. Ionomeric materials have long been used as layers of golf balls, particularly as inner or outer cover layers. These ionomers may be prepared by methods known in the art. These ionomer acid copolymers contain inter-chain ionic bonding. Metal ions such as sodium, lithium, zinc, and magnesium are typically used to neutralize some or all of the acid groups in the copolymer. An alternative may be the NCC to be used to react acid groups in the copolymer.

Nanocrystalline cellulose can be obtained from native cellulose fibers by an acid hydrolysis, giving rise to highly crystalline and rigid nanoparticles (generally referred to as nanowhiskers) which are shorter (100s to 1000 nanometers) than the nanofibrils obtained through the homogenization route.

A schematic diagram illustrating the various types of chemical modifications on NCC is provided below:

During manufacture, cellulose is milled and hydrolyzed to remove amorphous regions. The resulting nanocrystalline cellulose is then separated and concentrated before being modified for coating applications. Nanocrystalline cellulose can form stable suspensions or slurries with a latex or polymer solution that self-assemble into oriented films or coatings upon drying. Nanocrystalline cellulose provides structural reinforcement, reduced wear, and gas impermeability. Nanocrystalline cellulose material is light weight, biodegradable, non-toxic, cost-efficient, and recyclable. The golf balls of the present invention can include the nanocrystalline cellulose material or nanocellulose, methods, and constructions as described in the following publication-Peng, B. L., Dhar, N., Liu, H. L. and Tam, K. C. (2011). “Chemistry and applications of nanocrystalline cellulose and its derivatives: A nanotechnology perspective.”The Canadian Journal of Chemical Engineering 89 (5): 1191-1206, which is incorporated herein by reference in its entirety.

The nanocrystalline cellulose (NCC) material for usage in golf balls has many characteristics which are listed by way of example and without limitation. NCCs are rigid, rod-like crystals. The length of the nanocrystalline material may be from about 100 to 120 nm or, more preferably, about 110 nm. The diameter of the nanocrystalline cellulose material may have a diameter about 5 to 15 nm, or, more preferably about 10 nm. The tensile strength of the nanocrystalline cellulose material is about 7,000 to 14,000 MPa, or, more preferably, about 10,000 MPa. The elastic modulus of the nanocrystalline cellulose material may be about 125 to 175 GPa, or, more preferably about 150 GPa. Further details of the nanocrystalline cellulose material with regard to physical properties are provided below.

Physical Properties Properties NCC Length, nm 100-120 Diameter, nm 5-15 Specific Surface, m²/g ~400 Crystallinity Index, % >90 Tensile Strength, MPa 10,000 Elastic Modulus, GPa 150

A comparison chart of the reinforcement potential in relation to the properties of the nanocrystalline cellulose material and different materials is provided below.

Reinforcement Potential Tensile Young's Elongation Density strength modulus at break (g/cm³) (MPa) (GPa) (%) NCC 1.5 10,000 150 6.7 S/MWCNT 1.2-2.6 30,000 1000-1250   6-12.5 Carbon 1.7 4,000 230-240 1.4-1.8 Kevlar 29 1.44 2,800 183 4 Aramid 1.4 3,000-3,150 63-87 3.3-3.7 E-glass 2.5 2,000-3,600 70 2.5 S-glass 2.5 4,570 88 2.8 Kraft softwood ~1.5 ~700 ~20 ~2-4

In one embodiment, at least one or more of portions of the cover or intermediate layer comprises a blend of a polymer and about 1 to 10 pphr of a nanocrystalline cellulose material. In one embodiment, the polymer blended with the nanocrystalline cellulose material is a thermoset or thermoplastic material. The polymer may also be one or more of the following: thermoplastics, thermosets, ionomers, non-ionomers, polysaccharides; polyesters; polyamides; polypeptides; polyurethanes; polyureas, polyurethane-ureas; polyurea-urethanes; polyethylenes; polypropylenes; polyvinylchlorides; polystyrenes; polyphenols; polyvinyl pyrollidones; polyvinyl alcohols; ethylcelluloses; gar gums; metallocene-catalyzed polymers; polyvinyl formal resins; water soluble epoxy resins; urea-formaldehydes; polylysines; chitosans; polyvinyl acetates; and polymers containing αβ-unsaturated carboxylic acid groups, or the salts thereof.

In one embodiment, the cover comprises the nanocrystalline cellulose material and is an outer core layer, an inner cover layer, or an outer cover layer. In addition, the golf ball may further comprise a coating comprising the nanocrystalline cellulose material.

The compositions of the golf ball may also include other nanomaterials including, but not limited to, carbon nanotubes; Fullerenes; nanoscale titanium oxides; iron oxides; ceramics; modified ceramics, such as organic/inorganic hybrid polymers; metal and oxide powders (ultrafine and superfine); titanium dioxide particles; single-wall and multi-wall carbon nanotubes; polymer nanofibers; carbon nanofibrils; nitrides; carbides; sulfides; gold nanoparticles; and mixtures thereof.

The nanomaterials can be blended with thermoplastics, thermoplastic elastomers, rubbers, and thermoset materials useful in making golf ball components. The nanoparticulates can be incorporated either during blending operation such as in single or twin-screw extruders or in rubber mixing equipment like brabender or internal mixers. Also, the nanoparticulates can be blended in a reactor during the polymerization of thermoplastic or thermoset or rubbery materials.

Thermoplastic resins and rubbers for use as the matrix polymer and/or as an intercalant polymer, in the practice of this invention may vary widely. Illustrative of useful thermoplastic resins, which may be used alone or in admixture, include, but are not limited to, polylactones such as poly(pivalolactone), poly(caprolactone) and the like; polyurethanes derived from reaction of diisocyanates such as 1,5-naphthalene diisocyanate; p-phenylene diisocyanate, m-phenylene diisocyanate, 2,4-toluene diisocyanate, 4,4′-d iphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-diphenyl-methane diisocyanate, 3,3-′dimethyl-4,4′-biphenyl diisocyanate, 4,4′-diphenylisopropylidene diisocyanate, 3,3′-dimethyl-4,4′-diphenyl diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-biph-enyl diisocyanate, dianisidine diisocyanate, toluidine diisocyanate, hexamethylene diisocyanate, 4,4′-diisocyanatodiphenylmethane, and the like.

Also suitable are linear long-chain diols such as poly(tetramethylene adipate), poly(ethylene adipate), poly(1,4-butylene adipate), poly(ethylene succinate), poly(2,3-butylene succinate), polyether diols and the like; polycarbonates such as poly[methane bis(4-phenyl)carbonate], poly[1,1-ether bis(4-phenyl)carbonate], poly[diphenylmethane bis(4-phenyl)carbonate], poly[1,1-cyclohexane bis(4-phenyl)carbonate] and the like; polysulfones; polyethers; polyketones; polyamides such as poly(4-amino butyric acid), poly(hexamethylene adipamide), poly(6-aminohexanoic acid), poly(m-xylylene adipamide), poly(p-xylylene sebacamide), poly(2,2,2-trimethyl hexamethylene terephthalamide), poly(metaphenylene isophthalamide) (NOMEX®), poly(p-phenylene terephthalamide) (KEVLAR®), and the like; polyesters such as poly(ethylene azelate), poly(ethylene-1,5-naphthalate, poly(l,4-cyclohexane dimethylene terephthalate), poly(ethylene oxybenzoate) (A-TELL®), poly(para-hydroxy benzoate) (EKONOL®), poly(1,4-cyclohexylidene dimethylene terephthalate) (KODEL®), poly(1,4-cyclohexylidene dimethylene terephthalate) (KODEL®), polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terepthalate (“PTT”), and the like; poly(arylene oxides) such as poly(2,6-dimethyl-1,4-phenylene oxide), poly(2,6-diphenyl-1,4-phenylene oxide) and the like; poly(arylene sulfides) such as poly(phenylene sulfide), and the like.

Further suitable polymers include, but are not limited to polyetherimides; vinyl polymers and their copolymers such as polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride; polyvinyl butyral, polyvinylidene chloride, ethylene-vinyl acetate copolymers, and the like; polyacrylics, polyacrylate and their copolymers such as polyethyl acrylate, poly(n-butyl acrylate), polymethylmethacrylate, polyethyl methacrylate, poly(n-butyl methacrylate), poly(n-propyl methacrylate), polyacrylamide, polyacrylonitrile, polyacrylic acid, ethylene-acrylic acid copolymers, ethylene-vinyl alcohol copolymers acrylonitrile copolymers, methyl methacrylate-styrene copolymers, ethylene-ethyl acrylate copolymers, methacrylated butadiene-styrene copolymers, and the like; polyolefins such as low density poly(ethylene), poly(propylene), chlorinated low density poly(ethylene), poly(4-methyl-1-pentene), poly(ethylene), poly(styrene), and the like; ionomers; poly(epichlorohydrins); and polysulfones, such as the reaction product of the sodium salt of 2,2-bis(4-hydroxyphenyl)propane and 4,4′-dichlorodiphenyl sulfone; furan resins, such as poly(furan); cellulose ester plastics, such as cellulose acetate, cellulose acetate butyrate, cellulose propionate, and the like; silicones such as poly(dimethyl siloxane), poly(dimethyl siloxane), poly(dimethyl siloxane co-phenylmethyl siloxane), and the like; protein plastics; and blends of two or more of the foregoing.

Preferably, the nanomaterials can be blended with materials such as ionomers, copolyether-ester, copolyester-ester, copolyether-amide, copolyester-amide, thermoplastic urethanes, metallocene or single-site non-metallcene catalyzed polymers, polyamides, liquid crystal polymers, as well as other polymers mentioned in U.S. Pat. No. 6,124,389; U.S. Pat. No. 6,025,442; and U.S. Pat. No. 6,001,930, the disclosures of which are incorporated herein, in their entirety, by express reference thereto.

Vulcanizable and thermoplastic rubbers useful as the matrix polymer and/or as a water insoluble intercalant polymer, in the practice of this invention may also vary widely. Examples include but are not limited to, brominated butyl rubber, chlorinate butyl rubber, polyurethane elastomers, fluoroelastomers, polyester elastomers, polyvinylchloride, butadiene/acrylonitrile elastomers, silicone elastomers, poly(butadiene), poly(isoprene), poly(isobutylene), ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, sulfonated ethylene-propylene-diene terpolymers, poly(chloroprene), poly(2,3-dimethylbutadiene), poly(butadiene-pentadiene), chlorosulphonated poly(ethylenes), poly(sulfide) elastomers, block copolymers made up of segments of glassy or crystalline blocks such as poly(styrene), poly(vinyltoluene), poly(t-butyl styrene), polyesters and the like and the elastomeric blocks such as poly(butadiene), poly(isoprene), ethylene-propylene copolymers, ethylene-butylene copolymers, polyether and the like as for example the copolymers in poly(styrene)-poly(butadiene)-poly(styrene) block copolymer manufactured by Shell Chemical Company of Houston, Tex., under the trade name KRATON®.

In another embodiment, the core may comprise a core composition comprising a rubber based compound comprising cis-1,4-polybutadiene rubber, a crosslinking agent comprising a metallic salt of unsaturated carboxylic acid in an amount between 10 to 50 parts per hundred of rubber (pphr), a peroxide initiator, one or more filler materials, and optionally, organ sulfur compound are used to provide soft and resilient cores.

Golf balls of the present invention comprising nanocrystalline cellulose material may have a variety of further configurations. The golf balls can include one-piece, two-piece, multi-layer, and wound golf balls having a variety of core structures, intermediate layers, covers, and coatings.

Golf ball cores of the present invention may comprise a single, unitary layer, comprising the entire core from the center of the core to its outer periphery. Also, the core maybe a single, double, triple or more layer cores. Alternatively, the cores may comprise or consist of a center surrounded by at least one outer core layer. The center, innermost portion of such multi-layer cores is most often solid, but may be hollow or liquid-, gel-, gas-filled, or other types of cores. The outer core layer may be solid, or it may be a wound layer formed of a tensioned elastomeric or non-elastomeric material.

Referring to FIG. 1, a golf ball 10 of the present invention comprising a nanocrystalline cellulose material can include a core 12 and a cover 16 surrounding the core 12. Referring to FIG. 2, a golf ball 20 of the present invention can include a core 22, a cover 26, and at least one intermediate layer 24 disposed between the cover and the core. Each of the cover and core may include more than one layer; i.e., the golf ball can be a conventional three-piece wound ball, a two-piece ball, a ball having a multi-layer core and an intermediate layer or layers, etc. Thus, referring to FIG. 3, a golf ball 30 of the present invention can include a core 32, an inner cover layer 37 and outer cover layer 36, and at least one intermediate layer 34 disposed between the cover and the core. It will be appreciated that any number or type of intermediate layers may be used, as desired. It should also be noted that the nanocrystalline cellulose material may be used within any portion or layer of the golf ball.

The base rubber may comprise natural or synthetic rubbers. A preferred base rubber is 1,4-polybutadiene having a cis-structure of at least 40%, more preferably at least about 90%, and most preferably at least about 95%. Most preferably, the base rubber comprises high-Mooney-viscosity rubber. For example, in one embodiment, the polybutadiene rubber has high cis content of 95% and greater. Preferably, the base rubber has a Mooney viscosity greater than about 35, more preferably greater than about 50. Preferably, the polybutadiene rubber has a molecular weight greater than about 400,000 and a polydispersity of no greater than about 2. Examples of desirable polybutadiene rubbers include BUNA® CB1221 commercially available from Lanxess Corporation; UBEPOL® 360L and UBEPOL® 150L, commercially available from UBE Industries of Tokyo, Japan. If desired, the polybutadiene can also be mixed with other elastomers known in the art such as natural rubber, polyisoprene rubber and/or styrene-butadiene rubber in order to modify the properties of the core.

The crosslinking agent may comprise a metallic salt of unsaturated carboxylic acid in an amount between 10 to 50 parts per hundred of rubber (pphr). In one embodiment, the crosslinking agent may be in an amount of 10 parts per hundred of rubber (pphr). The crosslinking agent may be present in an amount greater than about 10 parts per hundred of rubber (pphr), preferably from about 10 to 50 parts per hundred of rubber (pphr), more preferably from about 25 to 35 parts per hundred of rubber (pphr).

Crosslinking agents are typically included to increase the hardness of the reaction product. The crosslinking agent must be present in an amount sufficient to crosslink a portion of the chains of polymers in the resilient polymer component. For example, the desired compression may be obtained by adjusting the amount of crosslinking. This may be achieved, for example, by altering the type and amount of crosslinking agent, a method well-known to those of ordinary skill in the art.

Examples include, but are not limited to, one or more metal salt diacrylates, dimethacrylates, and monomethacrylates, wherein the metal is magnesium, calcium, zinc, aluminum, sodium, lithium, or nickel. Preferred acrylates include zinc acrylate, zinc diacrylate, zinc methacrylate, zinc dimethacrylate, and mixtures thereof.

In one embodiment, the initiator may be a peroxide initiator in an amount between 0.25 to 2.5 pphr, and preferably between 0.25 to 1.5 pphr. The initiator can also be any known polymerization initiator which decomposes during the cure cycle. Suitable initiators include organic peroxide compounds, such as dicumyl peroxide; 1,1-di(t-butylperoxy) 3,3,5-trimethyl cyclohexane; a,a-bis (t-butylperoxy) diisopropylbenzene; 2,5-dimethyl-2,5 di(t-butylperoxy) hexane; di-t-butyl peroxide; and mixtures thereof. Other examples include, but are not limited to, VAROX® 231XL and Varox® DCP-R, commercially available from Elf Atochem of Philadelphia, Pa.; PERKODOX® BC and PERKODOX® 14, commercially available from Akzo Nobel of Chicago, Ill.; and ELASTOCHEM® DCP-70, commercially available from Rhein Chemie of Trenton, N.J.

It is well known that peroxide initiators are available in a variety of forms having different activity. The activity is typically defined by the “active oxygen content.” For example, PERKODOX® BC peroxide is 98% active and has an active oxygen content of 5.80%, whereas PERKODOX® DCP-70 is 70% active and has an active oxygen content of 4.18%. If the peroxide is present in pure form, it is preferably present in an amount of at least about 0.25 pphr, more preferably between about 0.35 pphr and about 2.5 pphr, and most preferably between about 0.5 pphr and about 2 pphr. Peroxides are also available in concentrate form, which are well-known to have differing activities, as described above. In this case, if concentrate peroxides are employed in the present invention, one skilled in the art would know that the concentrations suitable for pure peroxides are easily adjusted for concentrate peroxides by dividing by the activity. For example, 2 pphr of a pure peroxide is equivalent 4 pphr of a concentrate peroxide that is 50% active (i.e., 2 divided by 0.5=4).

Filler materials typically include materials such as tungsten, zinc oxide, barium sulfate, silica, calcium carbonate, zinc carbonate, metals, metal oxides and salts, regrind (recycled core material typically ground to about 30 mesh particle), high-Mooney-viscosity rubber regrind, and the like. Filler materials added to one or more portions of the golf ball typically include processing aids or compounds to affect rheological and mixing properties, density-modifying fillers, tear strength, or reinforcement fillers, and the like. The filler materials are generally inorganic, and suitable filler materials include numerous metals or metal oxides, such as zinc oxide and tin oxide, as well as barium sulfate, zinc sulfate, calcium carbonate, barium carbonate, clay, tungsten, tungsten carbide, an array of silicas, and mixtures thereof. Filler materials may also include various foaming agents or blowing agents which may be readily selected by one of ordinary skill in the art. Filler materials may include polymeric, ceramic, metal, and glass microspheres may be solid or hollow, and filled or unfilled. Filler materials are typically also added to one or more portions of the golf ball to modify the density thereof to conform to uniform golf ball standards. Filler materials may also be used to modify the weight of the center or at least one additional layer for specialty balls, e.g., a lower weight ball is preferred for a player having a low swing speed.

In one embodiment, the core composition of the golf ball may comprise an organo sulfur compound selected from a group consisting of: ZnPCTP, DTDS, DPDS, and mixtures thereof. In some formulations, optionally additional organa sulfur compounds like ZnPCTP or DTDS or DPDS or related materials may be incorporated from 0.25 to 2.5 pphr to provide additional soft and resilient property.

In one embodiment, the core composition of the golf ball may comprise one or more antioxidants. Typically, antioxidants are included in conventional rubber-based golf ball component compositions because antioxidants are included in the materials supplied by manufacturers of compounds used therein. Without being bound to any particular theory, higher amounts of antioxidant in the reaction product may result in less trans-isomer content because the antioxidants consume at least a portion of the free radical source. For example, a polybutadiene reaction product with 0.5 pphr of antioxidant cured at 335 degrees F. for 11 minutes results in about 15 percent trans-isomer content at an exterior surface of the center and about 13.4 percent at an interior location after the conversion reaction. In contrast, the same polybutadiene reaction product substantially free of antioxidants results in about 32 percent trans-isomer content at an exterior surface and about 21.4 percent at an interior location after the conversion reaction.

In one embodiment, the core has a range of hardness gradient less than 0 to 8, preferably a range from −4 to 8 in JIS C Scale, and more preferably or 0 to 4 in JIS C Scale. The core has a core surface hardness about 20 to 60 Shore D, preferably 25 to 56 Shore D, and most preferably 30 to 50 Shore D. The core has a flexural modulus from 2 to 35 kpsi, preferably 5 to 25 kpsi, and most preferably 10 to 20 kpsi.

In another embodiment, the golf ball further the golf ball further comprises one or more layers. Optionally, additional intermediate layers may be disposed between the core and cover. In one embodiment of the present invention, golf ball includes a core and a cover layer. In another embodiment, the golf ball includes a core, an intermediate layer, and a cover layer. An intermediate layer may be formed from a thermoplastic or thermoset material. In one embodiment, the intermediate layer has a thickness of 0.010 to 0.030 inches, preferably 0.015 to 0.025 inches, and more preferably 0.015 to 0.020 inches.

The golf ball may also include an inner and outer cover layer formed from a thermoplastic or thermoset material. In general, the cover layer, or any layer of a multiple layer cover, can be formed of suitable polymers such as the copolymers described herein, polyurethanes, or polyureas. The outer cover layer and/or the inner cover layer can comprise a light stable polyurethane, polyurea, and/or the copolymers described herein. In one embodiment, the outer cover is formed from a thermoplastic composition including ionomers, acid copolymers, thermoplastic urethanes as well as from the thermoset polyurethane or polyuria or expoy and cross-linkable rubber compositions including BR and non-BR formulations.

At least one of the cover layers comprises a material selected from a group consisting of: ionomeric material, vinyl resins, polyolefins, polyurethanes, polyureas, polyamides, acrylic resins, polyphenylene oxide resins, thermoplastic polyesters, thermoplastic vulcanized rubbers, fully-neutralized polymers, polycarbonates, polybutylene terephthalates, acrylonitriles, partially-neutralized polymers, and mixtures thereof.

For example, this golf ball can likewise include one or more homopolymeric or copolymeric cover materials, such as:

-   -   (1) Vinyl resins, such as those formed by the polymerization of         vinyl chloride, or by the copolymerization of vinyl chloride         with vinyl acetate, acrylic esters or vinylidene chloride;     -   (2) Polyolefins, such as polyethylene, polypropylene,         polybutylene and copolymers such as ethylene methylacrylate,         ethylene ethylacrylate, ethylene vinyl acetate, ethylene         methacrylic or ethylene acrylic acid or propylene acrylic acid         and copolymers and homopolymers produced using a single-site         catalyst;     -   (3) Polyurethanes, such as those prepared from polyols and         diisocyanates or polyisocyanates and those disclosed in U.S.         Pat. No. 5,334,673;     -   (4) Polyureas, such as those disclosed in U.S. Pat. No.         5,484,870;     -   (5) Polyamides, such as poly(hexamethylene adipamide) and others         prepared from diamines and dibasic acids, as well as those from         amino acids such as poly(caprolactam), and blends of polyamides         with SURLYN®, polyethylene, ethylene copolymers,         ethyl-propylene-non-conjugated diene terpolymer, and the like;     -   (6) Acrylic resins and blends of these resins with poly vinyl         chloride, elastomers, and the like;     -   (7) Thermoplastics, such as urethanes; olefinic thermoplastic         rubbers, such as blends of polyolefins with         ethylene-propylene-non-conjugated diene terpolymer; block         copolymers of styrene and butadiene, isoprene or         ethylene-butylene rubber; or copoly(ether-amide), such as         PEBAX®, sold by Atofina of Philadelphia, Pa.;     -   (8) Polyphenylene oxide resins or blends of polyphenylene oxide         with high impact polystyrene as sold under the trademark NORYL®         by Sabic Company of Pittsfield, Mass.;     -   (9) Thermoplastic polyesters, such as polyethylene         terephthalate, polybutylene terephthalate, polyethylene         terephthalate/glycol modified and elastomers sold under the         trademark HYTREL® by E.I. DuPont de Nemours & Co. of Wilmington,         Del.;     -   (10) Blends and alloys, including polycarbonate with         acrylonitrile butadiene styrene, polybutylene terephthalate,         polyethylene terephthalate, styrene maleic anhydride,         polyethylene, elastomers, and the like, and polyvinyl chloride         with acrylonitrile butadiene styrene or ethylene vinyl acetate         or other elastomers; and     -   (11) Blends of thermoplastic rubbers with polyethylene,         propylene, polyacetal, nylon, polyesters, cellulose esters, and         the like.

In a further embodiment, the cover of the golf balls may have a thickness of at least about 0.03 inches, preferably 0.03 to 0.125 inches, and more preferably from about 0.05 to 0.1 inches. In another embodiment, one of the inner and outer cover layers may have a thickness of less than about 0.05 inches. The golf balls also may have at least about 60 percent dimple coverage, preferably at least about 80 percent dimple coverage, of the surface area of the cover.

Also, the cover may have a thermoset or polyurethane composition comprising at least one of a UV absorber, a hindered amine light stabilizer, or an optical brightener. In another embodiment, the intermediate and inner cover layer may comprise a moisture resistant composition having a moisture vapor transition rate (MVTR) of 12.5 gmil/100 in2/day or less.

In one embodiment, the preparing of mixtures used in preps for a compression molding and cores may be made using a known core manufacturing procedure in the golf ball art. Any other materials used in forming either the golf ball center or any portion of the core, in accordance with invention, may be combined to form a mixture by any type of mixing known to one of ordinary skill in the art. Suitable types of mixing include single pass and multi-pass mixing, and the like. Suitable mixing equipment is well known to those of ordinary skill in the art, and such equipment may include a Banbury mixer, a two-roll mill, or a twin screw extruder. Conventional mixing speeds for combining polymers are typically used, although the speed must be high enough to impart substantially uniform dispersion of the constituents. Suitable mixing speeds and temperatures are well-known to those of ordinary skill in the art, or may be readily determined without undue experimentation.

The mixture may be subjected to a compression or injection molding process to obtain solid spheres for the center or hemispherical shells for forming an intermediate layer. The polymer mixture may be subjected to a molding cycle in which heat and pressure are applied while the mixture is confined within a mold. The cavity shape depends on the portion of the golf ball being formed. Any other materials used in forming either the golf ball center or any portion of the core, in accordance with the invention, may be combined to form a golf ball by an injection molding process, which is also well-known to one of ordinary skill in the art.

Based upon information and belief, the said 1.510″ solid cores can be made into a 2-piece cover golf ball by either compression or injection molding of a thermoplastic cover materials like Surlyn® ionomers or other suitable thermoplastic polymers and their blends. Similar or slightly modified core formulations may be used to produce cores with varying diameters from 1.53″ to 1.60″.

Based upon information and belief, the said 1.510″ solid cores may be covered with a casing layer by either compression or injection molding of a thermoplastic cover materials like Surlyn® ionomers or other suitable thermoplastic polymers and their blends and converted into a 3-piece golf ball by casting a thermoset polyurethane or polyurea cover layer around the casing layer or by injection or compression molding a thermoplastic urethane or suitable thermoplastic cover material. It also should be noted that the filler materials listed in the Examples may also include barium sulfate (BaSO4) and other fillers.

The foregoing detailed description describes the invention with reference to specific exemplary embodiments. However, it will be appreciated that various modifications and changes can be made without departing from the scope of the present invention as set forth in the appended claims. The detailed description is to be regarded as merely illustrative, rather than as restrictive, and all such modifications or changes, if any, are intended to fall within the scope of the present invention as described and set forth herein.

EXAMPLE I A Golf Ball Comprising a Nanocrystalline Cellulose Material

In a first embodiment of the present invention, a golf ball has a cover wherein one or more portions of the cover may be formed from a blend of thermoplastic or thermoset material and about 1 to 10 pphr of the nanocrystalline cellulose materials.

EXAMPLE II A Golf Ball Comprising a Nanocrystalline Cellulose Material

In a second embodiment of the present invention, a double cover ball having a core, a cover and an intermediate layer wherein the intermediate layer is formed a blend of thermoplastic or thermoset material and about 1 to 10 pphr of the nanocrystalline cellulose materials having one or more of the following: length of the nanocrystalline material may be from about 100 to 120 nm or, more preferably, about 110 nm, the diameter of the nanocrystalline cellulose material may have a diameter about 5 to 15 nm, or, more preferably about 10 nm, the tensile strength of the nanocrystalline cellulose material is about 7,000 to 14,000 MPa, or, more preferably, about 10,000 MPa, and the elastic modulus of the nanocrystalline cellulose material may be about 125 to 175 GPa, or, more preferably about 150 GPa.

The intermediate layer has a thickness of 0.010 to 0.030 inches, preferably 0.015 to 0.025 inches and more preferably 0.1015 to 0.020 inches. The core can be a solid core or a hollow or a fluid filled core. The core may also be a single or double or triple or more layer core.

The outer cover may be formed from a thermoplastic composition including, but not limited to, ionomers, acid copolymers, thermoplastic urethanes as well as from the thermoset polyurethane or polyurea or epoxy and cross-linkable rubber compositions including BR and non-BR formulations. The outer cover has a first Shore D hardness, the intermediate layer has a second Shore D hardness and an outer core surface has a third Shore D hardness wherein the first Shore D hardness is less than a second Shore D hardness by at least 5, preferably 8. The second Shore D hardness is greater than a third Shore D hardness by at least 5, preferably 8.

EXAMPLE III A Golf Ball Comprising a Nanocrystalline Cellulose Material

In a third embodiment of the present invention, a triple cover ball may have a core, a cover, an inner and outer cover layer and an intermediate layer.

The inner and outer cover layer may be formed from a blend of thermoplastic or thermoset material and about 1 to 10 pphr of the nanocrystalline cellulose materials. The innermost cover layer may have a Shore D hardness of 40 to 67 Shore D, preferably 50 to 65 Shore D, and most preferably 55 to 63 Shore D.

The outer cover layer may be formed from a thermoplastic composition including ionomers and thermoplastic urethanes as well as from thermoset polyurethane or polyurea or epoxy and cross-linkable rubber compositions including BR and non-BR formulations.

EXAMPLE IV A Golf Ball Comprising a Nanocrystalline Cellulose Material

In a fourth embodiment of the present invention, a triple cover ball may have a core, a cover, an inner and outer cover layer and an intermediate layer. The intermediate layer may be formed from a blend of thermoplastic or thermoset material and about 1 to 10 pphr of the nanocrystalline cellulose materials. The innermost cover layer may have a Shore D hardness of 40 to 67 Shore D, preferably 50 to 65 Shore D, and most preferably 55 to 63 Shore D.

The outer cover layer may be formed from a thermoplastic composition including ionomers and thermoplastic urethanes as well as from thermoset polyurethane or polyurea or epoxy and cross-linkable rubber compositions including BR and non-BR formulations.

The intermediate cover layer has a Shore D hardness of 40 to 67 Shore D, preferably 50 to 65 Shore D, and most preferably 55 to 63 Shore D. The outer cover may be formed from a thermoplastic composition including ionomers and thermoplastic urethanes as well as from a thermoset polyurethane or polyurea or epoxy and cross-linkable rubber compositions including BR and non-BR core formulations. Optionally both intermediate and innermost cover layer has an additional moisture barrier layer material to further protect the cores from the CoR loss.

Of course, the above are merely examples and additional configurations are possible incorporating the nanocrystalline cellulose material. For example, a three piece golf ball may be provided having a core, Surlyn® casing and urethane cover similar to Titleist's Pro V1 golf ball. In another example, a four piece golf ball may be provided having a dual core, Surlyn® casing and urethane cover similar to Titleist's Pro V1x golf ball. In a further example, a three piece golf ball may be provided having a dual core, and Surlyn® cover similar to Titleist's NXT Tour golf ball. In yet another example, the two piece golf ball may be provided having a core and a Surlyn® cover similar to Titleist's T-Solo golf ball.

The golf balls of the present invention can also include one or more other additives as desired in order to produce a golf ball with specific characteristics or properties. Suitable additives include, but are not limited to, chemical blowing and foaming agents, optical brighteners, coloring agents, fluorescent agents, whitening agents, UV absorbers, light stabilizers, defoaming agents, processing aids, mica, talc, nano-fillers, antioxidants, stabilizers, softening agents, fragrance components, plasticizers, impact modifiers, TiO2, acid copolymer wax, surfactants, and fillers, such as zinc oxide, tin oxide, barium sulfate, zinc sulfate, calcium oxide, calcium carbonate, zinc carbonate, barium carbonate, clay, tungsten, tungsten carbide, silica, lead silicate, regrind (recycled material), and mixtures thereof. Suitable additives are more fully described in, for example, U.S. Pat. No. 7,041,721, the entire disclosure of which is hereby incorporated herein by reference. Other optional additives can include fibers, flakes, particulates, microspheres, pre-expanded beads of glass, ceramic, metal or polymer, and the like which may be optionally foamed.

The core of the present invention may have an Atti compression of less than about 80, more preferably, between about 40 and about 80, and most preferably, between about 50 and about 70. In an alternative, low compression embodiment, the core has a compression less than about 20, more preferably less than about 10, and most preferably, 0. The overall outer diameter (“OD”) of the core is less than about 1.610 inches, preferably, no greater than 1.590 inches, more preferably between about 1.540 inches and about 1.580 inches, and most preferably between about 1.50 inches to about 1.570 inches. The OD of the casing of the golf balls of the present invention is preferably between 1.580 inches and about 1.640 inches, more preferably between about 1.590 inches to about 1.630 inches, and most preferably between about 1.600 inches to about 1.630 inches.

The present multilayer golf ball can have an overall diameter of any size. Although the United States Golf Association (“USGA”) specifications limit the minimum size of a competition golf ball to 1.680 inches. There is no specification as to the maximum diameter. Golf balls of any size, however, can be used for recreational play. The preferred diameter of the present golf balls is from about 1.680 inches to about 1.800 inches. The more preferred diameter is from about 1.680 inches to about 1.760 inches. The most preferred diameter is about 1.680 inches to about 1.740 inches.

In addition, the nanocrystalline cellulose material may be incorporated into a golf ball during manufacturing or may incorporated into other golf equipment and cosmetic improvements such as paints, inks, inserts for golf clubs, putters, irons, and woods, and in golf shoes and components thereof.

As used herein, the term “about,” used in connection with one or more numbers or numerical ranges, should be understood to refer to all such numbers, including all numbers in a range.

Other than in the operating examples, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials and others in the specification may be read as if prefaced by the word “about” even though the term “about” may not expressly appear with the value, amount or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, when numerical ranges of varying scope are set forth herein, it is contemplated that any combination of these values inclusive of the recited values may be used.

While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the objective stated above, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention. 

What is claimed is:
 1. A golf ball, comprising: a polybutadiene based core; and a cover disposed about the core; wherein at least one or more portions of the cover comprising a nano-cellulose material.
 2. The golf ball of claim 1, wherein the nano-cellulose material is nanocrystalline cellulose material.
 3. The golf ball of claim 1, wherein the core comprises: a rubber based compound comprising cis-1,4 polybutadiene rubber; a crosslinking agent comprising a metallic salt of unsaturated carboxylic acid in an amount between 10 to 50 parts per hundred of rubber; and a peroxide initiator.
 4. The golf ball of claim 1, wherein the cover comprises a blend of thermoplastic or thermoset material.
 5. The golf ball of claim 3, wherein the cover comprises about 1 to 10 pphr of the nanocrystalline cellulose material.
 6. The golf ball of claim 1, further comprising: an intermediate layer disposed between the core and the cover, wherein at least one or more portions of the cover or intermediate layer comprises a blend of thermoplastic or thermoset material and about 1 to 10 pphr of a nanocrystalline cellulose material.
 7. The golf ball of claim 1, wherein the cover comprises the nanocrystalline cellulose material and is an outer core layer, an inner cover layer, or an outer cover layer.
 8. The golf ball of claim 1, further comprising a coating comprising the nanocyrstalline cellulose material.
 9. The golf ball of claim 1, wherein the nanocrystalline cellulose material has a length from about 100 to 120 nm.
 10. The golf ball of claim 9, wherein the length of the nanocrystalline cellulose material is about 110 nm.
 11. The golf ball of claim 1, wherein the nanocrystalline cellulose material has a diameter about 5 to 15 nm.
 12. The golf of claim 11, wherein the diameter of the nanocrystalline cellulose material has a diameter of about 10 nm.
 13. The golf ball of claim 1, wherein the nanocrystalline cellulose material has a tensile strength of about 7,000 to 14,000 MPa.
 14. The golf ball of claim 13, wherein the tensile strength of the nanocrystalline cellulose material is about 10,000 MPa.
 15. The golf ball of claim 1, wherein the nanocrystalline cellulose material has an elastic modulus from about 125 to 175 GPa.
 16. The golf ball of claim 15, wherein the elastic modulus of the nanocrystalline cellulose material is about 150 GPa.
 17. A golf ball, comprising: a polybutadiene based core; an intermediate layer disposed between the core and a cover, the intermediate layer comprises nanocrystalline cellulose material.
 18. The golf ball of claim 17, wherein the intermediate layer comprises a blend of thermoplastic or thermoset material.
 19. The golf ball of claim 17, wherein the intermediate layer comprises about 1 to 10 pphr of the nanocrystalline cellulose material.
 20. A method of manufacturing a golf ball, comprising: providing at least one or more portions of the cover or intermediate layer comprising a nanocrystalline cellulose material. 